At present, various animation effects in a mobile terminal bring a good experience to a user as the mobile terminal is enhanced in terms of its configuration, and three-dimensional animation effects, including rotary turning of a page and rotation of a cube, especially present very good visual perception, where generation of a perspective image is crucial to present these three-dimension animation effects.
As illustrated in FIG. 1, a visual effect of a cube can be presented simply by performing perspective transformation on an original image toward the left and the right respectively and then splicing, and a special rotation effect of a cube is achieved by changing the perspective angles of perspective images on the left and the right sequentially resulting in a plurality of three-dimension images and then combining them in a plurality of frames and displaying them rapidly and consecutively. Generally, a frame rate above 15 frames per second is required for relatively smooth visual perception, so the two perspective images on the left and the right have to be generated and displayed in 66 milliseconds. In a real system, a CPU may be occupied by other tasks, so there is actually a period of time shorter than 66 milliseconds for generation of the perspective images.
In an existing method for generating a perspective image, each of pixel points of an original image is duplicated according to a function group from
            x      ′        =          F      ⁡              (                  x          ,          y                )                        y      ′        =          G      ⁡              (                  x          ,          y                )            a coordinate space constituted of the x axis and the y axis into a coordinate space constituted of the x′ axis and the y′ axis, where floating-point and trigonometric function operations involved in the functions F (x, y) and G (x, y) are rather demanding in terms of the performance of a CPU.
A period of time for generation of perspective images combined in a frame is limited by the performance of a CPU, the size of an image and other factors. In a general low- to mid-end cellular phone system of CDMA, a 240×400 display screen and an ARM9 CPU at 192 MHz, for example, are used, and then there are actually only 40 milliseconds for generation of perspective images combined in a frame after the CPU is occupied by display and other tasks, so there are only 20 milliseconds on average for generation of a perspective image, which may be impractical with the foregoing perspective transformation method.